This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A022124 #39 Jun 15 2022 01:53:06
%S A022124 3,13,16,29,45,74,119,193,312,505,817,1322,2139,3461,5600,9061,14661,
%T A022124 23722,38383,62105,100488,162593,263081,425674,688755,1114429,1803184,
%U A022124 2917613,4720797,7638410,12359207
%N A022124 Fibonacci sequence beginning 3, 13.
%C A022124 For n >= 5, 4*a(n) is the number of ways to tile, with squares and dominoes, a horizontal strip of length n+1 that begins and ends with two vertical strips of heights 3 and 2. As an example, 4*a(7) = 4*193 = 772 is the number of ways to tile this figure (of length 8) with squares and dominoes.
%C A022124 ._ _
%C A022124 |_|_ _|_|
%C A022124 |_|_|_______|_|_|
%C A022124 |_|_|_|_|_|_|_|_| - _Reeva Bohra_ and _Greg Dresden_, Aug 17 2021
%H A022124 Harvey P. Dale, <a href="/A022124/b022124.txt">Table of n, a(n) for n = 0..1000</a>
%H A022124 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>
%H A022124 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (1,1).
%F A022124 G.f.: (3+10x)/(1-x-x^2). - _Philippe Deléham_, Nov 19 2008
%F A022124 a(n) = 5*Lucas(n+1) - 2*Fibonacci(n+1). - _Lechoslaw Ratajczak_, Apr 04 2021
%t A022124 LinearRecurrence[{1,1},{3,13},40] (* _Harvey P. Dale_, Jun 08 2016 *)
%Y A022124 Cf. A000032, A000045, A022382.
%K A022124 nonn,easy
%O A022124 0,1
%A A022124 _N. J. A. Sloane_